diff options
Diffstat (limited to 'arch/i386/kernel/process.c')
| -rw-r--r-- | arch/i386/kernel/process.c | 99 |
1 files changed, 83 insertions, 16 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index c641056233a6..7845d480c293 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -48,6 +48,7 @@ #include <asm/i387.h> #include <asm/desc.h> #include <asm/vm86.h> +#include <asm/idle.h> #ifdef CONFIG_MATH_EMULATION #include <asm/math_emu.h> #endif @@ -80,6 +81,42 @@ void (*pm_idle)(void); EXPORT_SYMBOL(pm_idle); static DEFINE_PER_CPU(unsigned int, cpu_idle_state); +static ATOMIC_NOTIFIER_HEAD(idle_notifier); + +void idle_notifier_register(struct notifier_block *n) +{ + atomic_notifier_chain_register(&idle_notifier, n); +} + +void idle_notifier_unregister(struct notifier_block *n) +{ + atomic_notifier_chain_unregister(&idle_notifier, n); +} + +static DEFINE_PER_CPU(volatile unsigned long, idle_state); + +void enter_idle(void) +{ + /* needs to be atomic w.r.t. interrupts, not against other CPUs */ + __set_bit(0, &__get_cpu_var(idle_state)); + atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL); +} + +static void __exit_idle(void) +{ + /* needs to be atomic w.r.t. interrupts, not against other CPUs */ + if (__test_and_clear_bit(0, &__get_cpu_var(idle_state)) == 0) + return; + atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL); +} + +void exit_idle(void) +{ + if (current->pid) + return; + __exit_idle(); +} + void disable_hlt(void) { hlt_counter++; @@ -130,6 +167,7 @@ EXPORT_SYMBOL(default_idle); */ static void poll_idle (void) { + local_irq_enable(); cpu_relax(); } @@ -189,7 +227,16 @@ void cpu_idle(void) play_dead(); __get_cpu_var(irq_stat).idle_timestamp = jiffies; + + /* + * Idle routines should keep interrupts disabled + * from here on, until they go to idle. + * Otherwise, idle callbacks can misfire. + */ + local_irq_disable(); + enter_idle(); idle(); + __exit_idle(); } preempt_enable_no_resched(); schedule(); @@ -243,7 +290,11 @@ void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) __monitor((void *)¤t_thread_info()->flags, 0, 0); smp_mb(); if (!need_resched()) - __mwait(eax, ecx); + __sti_mwait(eax, ecx); + else + local_irq_enable(); + } else { + local_irq_enable(); } } @@ -308,8 +359,8 @@ void show_regs(struct pt_regs * regs) regs->eax,regs->ebx,regs->ecx,regs->edx); printk("ESI: %08lx EDI: %08lx EBP: %08lx", regs->esi, regs->edi, regs->ebp); - printk(" DS: %04x ES: %04x GS: %04x\n", - 0xffff & regs->xds,0xffff & regs->xes, 0xffff & regs->xgs); + printk(" DS: %04x ES: %04x FS: %04x\n", + 0xffff & regs->xds,0xffff & regs->xes, 0xffff & regs->xfs); cr0 = read_cr0(); cr2 = read_cr2(); @@ -340,7 +391,7 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) regs.xds = __USER_DS; regs.xes = __USER_DS; - regs.xgs = __KERNEL_PDA; + regs.xfs = __KERNEL_PDA; regs.orig_eax = -1; regs.eip = (unsigned long) kernel_thread_helper; regs.xcs = __KERNEL_CS | get_kernel_rpl(); @@ -425,7 +476,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp, p->thread.eip = (unsigned long) ret_from_fork; - savesegment(fs,p->thread.fs); + savesegment(gs,p->thread.gs); tsk = current; if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { @@ -501,8 +552,8 @@ void dump_thread(struct pt_regs * regs, struct user * dump) dump->regs.eax = regs->eax; dump->regs.ds = regs->xds; dump->regs.es = regs->xes; - savesegment(fs,dump->regs.fs); - dump->regs.gs = regs->xgs; + dump->regs.fs = regs->xfs; + savesegment(gs,dump->regs.gs); dump->regs.orig_eax = regs->orig_eax; dump->regs.eip = regs->eip; dump->regs.cs = regs->xcs; @@ -653,7 +704,7 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas load_esp0(tss, next); /* - * Save away %fs. No need to save %gs, as it was saved on the + * Save away %gs. No need to save %fs, as it was saved on the * stack on entry. No need to save %es and %ds, as those are * always kernel segments while inside the kernel. Doing this * before setting the new TLS descriptors avoids the situation @@ -662,7 +713,7 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas * used %fs or %gs (it does not today), or if the kernel is * running inside of a hypervisor layer. */ - savesegment(fs, prev->fs); + savesegment(gs, prev->gs); /* * Load the per-thread Thread-Local Storage descriptor. @@ -670,14 +721,13 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas load_TLS(next, cpu); /* - * Restore %fs if needed. - * - * Glibc normally makes %fs be zero. + * Restore IOPL if needed. In normal use, the flags restore + * in the switch assembly will handle this. But if the kernel + * is running virtualized at a non-zero CPL, the popf will + * not restore flags, so it must be done in a separate step. */ - if (unlikely(prev->fs | next->fs)) - loadsegment(fs, next->fs); - - write_pda(pcurrent, next_p); + if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) + set_iopl_mask(next->iopl); /* * Now maybe handle debug registers and/or IO bitmaps @@ -688,6 +738,15 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas disable_tsc(prev_p, next_p); + /* + * Leave lazy mode, flushing any hypercalls made here. + * This must be done before restoring TLS segments so + * the GDT and LDT are properly updated, and must be + * done before math_state_restore, so the TS bit is up + * to date. + */ + arch_leave_lazy_cpu_mode(); + /* If the task has used fpu the last 5 timeslices, just do a full * restore of the math state immediately to avoid the trap; the * chances of needing FPU soon are obviously high now @@ -695,6 +754,14 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas if (next_p->fpu_counter > 5) math_state_restore(); + /* + * Restore %gs if needed (which is common) + */ + if (prev->gs | next->gs) + loadsegment(gs, next->gs); + + write_pda(pcurrent, next_p); + return prev_p; } |